1. Field of the Invention
The present invention relates to a method and an apparatus for performing target search on an optical storage disc, and more particularly, to a method and an apparatus for performing target search on an optical storage disc according to a hybrid address signal.
2. Description of the Prior Art
As the data processing speed of computer systems greatly increases and the requirement of more massive data storage is correspondingly introduced, optical storage discs that are cost-effective and compact while having larger storage volumes and high access speeds have become popular storage media. Accordingly, an optical storage device for accessing the optical storage discs becomes essential and necessary. Digital Versatile Discs (DVDs) and DVD drives are typical of the optical storage discs and optical storage devices mentioned above, respectively. When an optical storage device is going to read specific data within an optical storage disc, the optical storage device firstly performs a target search on the optical storage disc to find a location of the specific data. The optical storage device then compares address information read through an optical pickup module of the optical storage device from the optical storage disc with a target address. If the address information read through the optical pickup module matches with the target address, the target search is complete.
According to a prior art method of target search, the address information can be address information of physical wobbles on the optical storage disc, i.e. physical addresses. Normally, pre-grooves of a blank optical storage disc include the information of the physical addresses. However, it is not easy to read the physical wobbles if data is already written on the optical storage disc since the data writing process usually degrades the quality of the physical wobbles. As a result, the optical storage device is either unable to perform the target search or performs the target search inaccurately.
According to another prior art method of target search, the address information can be address information corresponding to storage information stored within the optical storage disc, i.e. logical addresses. However, the accuracy of the logical addresses corresponds to the accuracy of a location of the storage information stored within the optical storage disc. If data recording shift when writing the storage information to the optical storage disc occurs, the target search performed according to the logical addresses will be inaccurate due to the data recording shift.
As mentioned above, neither the prior art method of target search according to the physical addresses nor the prior art method of target search according to the logical addresses will ensure that the optical storage device correctly performs the target search.